Cylinder reconditioning tool



March .5, 1935.

CYLINDER RECONDITIONING TOOL Filed July 12, 1953 E. D. GREEN 1,993,004

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ATTORNEY Patented Mar. 5, 1935 UNITED STATES PATENT OFFICE 7 1,993,004 I g CYLINDER REGONDITIONING 'rooL Eliot D. Green, San Francisco, Calif. Application July 12, 1933, Serial No. 680,071

5 Claims.

My invention relates to tools for reconditioning engine cylinders which have become worn through use, and particularly to hand tools for reconditioning automotive motor cylinders.

After prolonged periods of use automotive and other internal combustion engine cylinders become worn, the wear being non-uniform, so that the cross section of the cylinder becomes slightly oval with the long axis perpendicular to the plane of the crank shaft. The greatest wear occurs on the side of the cylinder which receives the thrust due to the reaction of the crank shaft on the explosion stroke of the piston. The actual wearing surfaces are the piston rings, and since the upper ring must necessarily be spaced slightly below the piston head, the extreme upper end of the cylinder may remain nearly round, the wear starting slightly below, forming a nearly semi-circular or crescent shaped ridge at the top of the cylinder.

With a cylinder in this condition, if the worn piston rings be replaced, the upper ring, being a few thousandths of an inch wider than the worn one, strikes against this ridge, causing noisy operation of the motor. Frequently, moreover, the impact of the new ring against the ridge will be sufficiently severe so that the ring will be broken, causing the possibility of much greater damage to the cylinder. These difficulties may obviously be avoided by machining out'the ridge, leaving the entire cylinder of slightly oval cross section, but giving it a prolonged period of useful life before a complete reboring operation is necessary.

Among the objects of this invention are: To provide a tool for cutting away the ridges in worn internal combustion motor cylinders; to provide a tool of the character described which can effectively be used without entirely dismantling the motor; to provide a tool which will remove the projecting ridge, but which cannot cut below the general level of the cylinder wall and thus permanently damage the cylinder; to provide a tool which is self-centering and which may be used to recondition cylinders of any diameter throughout a wide range; and to provide a tool which is simple, portable, and rugged, and which does not require a high degree of skill to operate.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of my invention herein described, as various forms may be adopted within the scope of the claims.

In the drawing which illustrates a preferred embodiment of my invention:

Figure 1 is a side view in elevation of my invention as applied to a cylinder.

Figure 2 is a top view in elevation of the device as adju'sted;

Figure 3 is a sectional view applied to the ridge.

Figure 4 is a sectional view taken as indicated by the line 4-4 in Figure 3.

The broad aspect of my invention will be more apparent from a detailed description of the preshowingthe cutter 'ferred embodiment shown in the'drawing, in

which the reconditioning tool comprises a support blockl having a flat base a piston head 4 which is fitted to the cylinder 5 to be reconditioned. The ridge 6 to be removed, is shown somewhat enlarged for clearness.

Preferably formed integrally with the base is an upright portion '7, this portion being hollowed out to form a cutter recess 9. At the same time a portion of the side wall 10 is removed, at one end of the tool, thus leaving at the two sides of the recess a pair of guide edges 11-11, which are preferably sharpened as shown and which are adapted'to contact the wall of the cylinder. As these guides are spaced some distance apart, the arc of the cylinder wall included between the guides will have a different curvature in different sizes of cylinders, and any cutter attached without adjustment to the upright portion '1 would be operable'to remove the ridge in one size of cylinder only. I

I have therefore provided means for adjusting the relative position of my cutter to the guides, or when the guides are touching the cylinder wall, to that wall.

A rotatable bearing 12 is mounted on the top wall l4 of the upright portion, this bearing extending parallel to the cylinder wall, or at right angles to the base 2. This bearing may rotate freely but may also be locked solidly in any degree of rotation by a thumbscrew 15, extending through the top wall 14 to engage the bearing.

I then drill a longitudinal hole through the bearing, this hole being off center or away from the axis of the bearing. A cutter shaft 16 is positioned in this hole, one end projecting into the cutter recess 9 and being provided with a cutter 1'7 held on by a cutter nut 19. The cutter is provided with peripheral teeth 20, the cutting edge being parallel to the shaft and cylinder wall. The upper end of the shaft is preferably provided with a universal joint 21, a shaft extension 22 being adapted to be gripped by the chuck of a 2 adapted to rest on rotating device, such as an electric drill, for example. The off-center mounting of the cutter shaft in the bearing 12 forms an eccentric by which the position of the cutter may be adjusted relative to the guides or cylinder wall, by rotation of the bearing. Knurling 24 is provided to facilitate rotation.

In use, the cylinder head of the engine to be reconditioned is removed, and the tool placed with the flat base resting on the piston head. The engine crank shaft is turned until the piston drops and both the guides 11'11 and the cutter are below the ridge to be removed. The thumbscrew 15 is then loosened, and the bearing 12 rotated until the guide edges 11-11 and the teeth 20 of the cutter are all three in contact with the cylinder wall. The bearing is then locked against further rotation with the thumbscrew, and the tool is ready to cut. Figure 2 shows the relation of the cutter and guides after this adjustment has been made.

The engine crank shaft is againrotated until the piston rises to the point where the cutter alone is opposite the ridge, as shown in Figures 3 and 4, An electric drill or similar rotating device is attached to the shaft extension, and the cutter rotated, pressure on the tool forcing the cutter against the ridge will cause the ridge to be removed at that point, the guides, however, coming against the cylinder wall below the ridge to prevent more metal being removed than is contained in the ridge. ;After the tool has been operated all around the periphery of the cylinderwall the ridge is completely removed, the surface remaining being an exact extension of the cylinder wall in which the piston travels.

The tool, therefore, after being adjusted to the particular size of cylinder, cannot remove more than the ridge. The one tool, because of the adjustability ofthe cutter will operate successfully in all sizes of cylinders from the smallest one in which the base 2 will fit up to the very largest.

I claim:

1. A tool for cutting ridges from worn cylinders comprising a support block adapted to rest on a piston cylinder head and free to move thereon within said cylinder, spaced guides on said block adapted to be the sole contact the wall of said cylinder, a cutter mounted on saidblock between said guides, means for adjusting the distance of said cutter from said wall when said guides are in contact with said wall, and means for locking said cutter in the desired position.

2. A tool for cutting ridges from worn cylinders comprising a support block adapted to rest on a piston cylinder head and free to move thereon within said cylinder, spaced guides on said block adapted to be the sole contact the wall or" said cylinder, a cutter mounted on said block between said guides, means for adjusting the distance of said cutter from said wall when said guides are in contact with said wall, means for locking said cutter in the desired position, and means for rotating said cutter.

3. A tool for removing ridges from worn cylinders comprising a support block adapted to rest on a piston cylinder head and free to move thereon within said cylinder, said block having a recess therein opening toward the side wall of said cylinder, the sides of said recess being adapted to be the sole contact with said wall, a rotatable cutter within said recess journaled on said block and having a peripheral cutting face parallel with said side walls, means for adjusting said cutter on said block with relation to said Wall, and means for rotating said cutter.

4. A tool for removing ridges from worn cylinders comprising a support block adapted to rest on a piston cylinder head within said cylinder and free to move thereon, said blockhaving a recess therein opening toward the side wall of said cylinder, the sides of said recess being adapted to be the sole contact with said wall, a bearing rotatably mounted on said block above said recess parallel with said side wall, a cutter shaft passing through said bearing apart from the axis of said bearing, and extending into said recess, a cutter mounted on the end of said shaft within said bearing, and means for locking said bearing at any desired degree of rotation. 5. A tool for removing ridges from worn cylinders comprising a support block adapted to rest on a piston cylinder head within said cylinder and free to move thereon, said block having a recess therein opening toward the side wall of said cylinder, the sides of said recess being adapted to be the sole contact with said wall, a bearing rotatably mounted on said block above said recess parallel with said side wall, a cutter shaft passing through said bearing apart from the axis of said bearing, and extending into said recess, a cutter mounted on the end of said shaft within said bearing, the other end of said shaft being adapted to be attached to a rotating device, and a uni versal joint insaid shaft adjacent the upper end of said bearing.

ELIOT D. GREEN. 

